In many industrial processes and in fluid production systems, a slurry of solids suspended in a liquid is produced and it becomes necessary to separate the solids from the liquids so that each material may be treated in ways that will make disposal or use of the treated materials both economical and environmentally effective. In most such processes or systems, the slurry material is fed to a filter apparatus which may take many forms including a belt press, a vacuum filter or a pressure filter. In one form of pressure filtration apparatus a pair of plate members form an internal space chamber separated by a filter media. The plate members are pressed together at mating surfaces with the filter media positioned between the mating surfaces and spread across the interior space separating one plate from the other plate. Slurry materials are fed into the chamber while filtrate liquids are taken away leaving behind the solids of the slurry accumulated on the filter media. After a sufficient amount of solid materials have been accumulated, the plates are separated and the filter media with the accumulated solids is replaced and the filtration process is then repeated with a clean filter media. The filtrate fluid and solids are then separately used, treated or disposed of in an acceptable manner.